Field of the Invention
This invention relates to a method for using cellular glass blocks, cellular glass nodules, hollow glass spheres, or other buoyant glass materials to attenuate oil fire, limit thermal radiation from an oil fire, and reduce the risk of boil-over phenomenon. Cellular glass blocks, cellular glass nodules, hollow glass spheres, or other buoyant glass products may be deployed passively, prior to an ignition event, or actively, as a response to an ignition event to provide control. Cellular glass or other buoyant glass materials may be in any physical shape such as block, sheet, aggregate, or nodule. While the descriptions herein focus on oil fires, one of ordinary skill in the art would understand that these methods could be applied not only to oil but also to all other similar hydrocarbon liquids. For convenience, the term “oil” will refer to all such hydrocarbons.
Background of the Invention
Oil fires are dangerous and often disastrous industrial events. Depending on the type of oil fuel, these fires can reach extremely high temperatures and result in the phenomenon known as “boil over”. Boil over may occur during an oil fire when a liquid phase in the oil vaporizes, causing the oil to boil, and results in spillage and catastrophic spreading of burning oil near the storage vessel.
A boil over can occur in crude oil tank fires when a “hot zone” of dense, hot fuel descends through the crude and reaches any water base. The water turns to steam, expanding in the order of 1500:1. This steam pushes up through the crude, taking fuel with it and creating a “fireball” above the tank. Boil overs have spread burning crude several tank diameters from the source, thus escalating the incident and endangering fire responders.
Buoyant glass products can be applied to the surface of oil, either passively before the ignition event, or as a response to the ignition event, to attenuate oil fires, limit thermal radiation from oil fires, and reduce the risk of boil over phenomenon from vaporization of the liquid phase. This attenuation can increase the amount of time one has to deploy firefighting measures, potentially saving lives and damage to adjacent equipment.
One buoyant glass product that could be utilized to reduce the risks of oil boil over includes cellular glass. The use of cellular glass as a thermal insulating material is well known. Cellular glass is an inorganic closed-cell material with high resistance to fire, moisture, vermin and mold growth. Cellular glass has been made in the past by processes disclosed in a number of patents, such as U.S. Pat. Nos. 2,255,238, 2,322,581, and 2,156,457. This prior art illustrates the making of cellular glass blocks for thermal insulation. As one of ordinary skill in the art is aware, the process includes mixing powdered glass material with a cellulating agent and partially filling a mold with the powdery mixture. The mold is heated until the powdery mixture softens, coalesces and the cellulating agent reacts to cellulate in the mixture to produce a bun of cellular glass. The bun is then annealed and cut or trimmed into a desired shape.
Cellular glass has many desirable properties, including dimensional stability, low density, low thermal conductivity, and high compressive strength. Since cellular glass is inorganic and made primarily from glass, it has a natural ability to attenuate thermal radiation and resist fire for extended periods of time. Cellular glass is specified on many industrial applications, such as pipe and vessel insulation, as well as in many building insulation applications. The cellular glass insulation properties are due in part to the ability of cellular glass to resist fire and protect equipment from thermal damage. Since cellular glass is closed-cell and lightweight, it is buoyant on most liquids including water, liquid natural gas (LNG) and oils. During World War II, for example, cellular glass was used to float nets in harbors to prevent enemy submarines from entering freely. More recently, the buoyancy and fire resistant properties of cellular glass have made it an ideal component for LNG pool fire suppression systems.
Glass spheres and other buoyant glasses will have similar performance characteristics as cellular glass when considering this invention.
Cellular glass has been utilized in various applications, such as pipe and vessel insulation, to limit damage to mechanical systems as a result of fires. These are largely protective measures against external thermal events that have the potential to damage unprotected equipment, and are not used to attenuate oil fires, limit thermal radiation from oil fires, and reduce the risk of boil over phenomenon.
Accordingly, it is an object of the present invention to provide an improved product and method, using cellular glass or other similar buoyant glass materials, to attenuate oil fires, limit thermal radiation from oil fires, and reduce the risk of boil over phenomenon.